<nz-select [(ngModel)]="selectedCloumn" [nzPlaceHolder]="placeholder" nzAllowClear (ngModelChange)="selectedCloumnChange.emit($event)">
  <nz-option *ngFor="let item of cloumns" [nzLabel]="item.displayName" [nzValue]="item">
  </nz-option>
</nz-select>
